Digiday reports that Google has implemented the tracking system it described last month, allowing it to see whether people seeing ads for local stores do in fact visit them.

If someone conducts a Google mobile search for “screwdrivers,” for instance, a local hardware store could bid to have its store listing served to that user. By pairing that person’s location data with its database of store listings, Google can see if the person who saw that ad subsequently visited the store.

Google can do this by default on Android devices – it’s one of the things you agree to in the small-print when you switch on location services – and on iOS devices when people use Google apps.

It’s effectively the real-world equivalent of cookies. When you’re exposed to an ad for the Acme Hardware Store, a cookie will often be placed on your PC. When you visit the Acme website, it can read that cookie and see that the ad worked. This does the same thing for visits to physical stores.

You’d have thought that when you’re spending half a billion dollars on marketing a phone, you might be able to decide your strategy beforehand. So far, Motorola seems to be suffering a bad case of indecisiveness, reports Business Insider, deleting the above tweet and revising two ads.

Two Attorneys General have written to Google to ask why it profits from advertising on YouTube videos which “depict or even promote dangerous or illegal activities.”

The letter follows the publication of a report by the Digital Citizens Alliance entitled Google, YouTube and Evildoers: Too Close for Comfort, presented to the National Association of Attorneys General last month. DCA Executive Director Tom Galvin commented then:

Google has allowed thousands of videos to exist on YouTube that offer drugs, prostitution, forged passports, counterfeits and content theft. Worse, they have profited from them by running ads in conjunction with these videos. Hopefully, the attorneys general will be able to get answers others have failed to get. Namely why such an important, otherwise great company is putting profit over the safety of Internet users. When Google finally takes steps to ensure these dangerous videos are gone for good from YouTube, the Internet will be a safer place.

Given fierce rivalry between Microsoft and Google, however, it pays to be a little circumspect in giving too much weight to organisations whose sources of funding are not clearly stated. We’ll await Google’s response with interest.

The vast majority of Google’s revenue comes from ad sales, with Google leading the market in the sale of mobile ads in particular.